Oil field derrick or the like



c. FOX.

L F D DERRICK OR THE LIK Jan. 19, 1943.

Filed Aug. 13,1940.

2' Sheets-Sheet l 7 Jan. 19, 1943.

c. L. FOX 2,308,652 OIL FIELD DERRICK OR THE LikE Filed Aug; 15,1940-2'Shets She et2 Patented Jan. 19, 1943 worse sra'rs My inventionrelates to improvements in the construction of fabricated structuralsteel derricks especially, although not exclusively, adapted for use indrilling and operating oil wells and the like.

The primary object of my invention is to provide an improved arrangementand proportioning of leg sections, girts and diagonal braces whereby thesafe load and wind load capacities are materially increased as well asgreater resistance to loosening due to vibration caused by drilling andother operations.

Another important object of my invention is to provide a stronger, morerigid and more easily connected joint between related leg sections,characterized by intermediate braced leg columns at the same distancethroughout the height of the legs, and by staggered leg section joints.

Other important objects and advantages of my invention will be apparentfrom a reading of the following description of the appended drawings,wherein for purposes of illustration a preferred embodiment of myinvention is shown.

In the drawings- Figure 1 is a general perspectiveview of theembodiment.

Figure 2 is a fragmentary elevational view of the rotary front of thederrick showing the starting legs comprising two sections and the twointermediate sections located immediately thereabove.

Figure 3 is a fragmentary elevational view of the ladder or forge sideof the derrick showing the starting legs comprising two sections and thetwo intermediate sections located immediately thereabove.

Figure 4 is an enlarged perspective view showing a typical intermediatesection.

Figure 5 is a side elevational View showing a group of typicalintermediate sections.

Figure 6 is a side elevational view showing a group of typical topsections.

Figure 7 is an enlarged fragmentary horizontal sectional view takenthrough a corner of the derrick.

Referring in detail to the drawings, my improved derrick comprises fourlegs designated by the numeral 5. The first and second horizontal girtsB and I extend across three sides of the derrick but are abbreviated onthe fourth side as indicated by the numerals 6' and I, so as to providefor the V-opening 8. All of the upwardly succeeding girts 9, Ill, etc.,extend across all four sides of the derrick and are vertically spaced atthe same intervals as the first two girts 6 and 1 at the distancerequired by present American Petroleum Institute specifications.

There are four diagonal braces H, l2, l3 and M, respectively, in eachpanel of the derrick. These diagonal braces are connected by securing toupper and lower plates l5 and [6 to extend vertically above and belowthemiddle points of the girts, with the outer ends of the braces se--cured to the legs 5 at points midway between the adjacent girts, so asto form a reclining diamond form of bracing in each panel.

This method of applying the bracing greatly relieves the load heretoforethrown on the girts, reduces the unsupported length of the legs 5, andeliminates the crossing of any brace over the other. In this way thebraces are made stress carrying members and the amount of stress on anyindividual diagonal brace is only a fraction of the actual safe loadcapacity'for the size of brace used in accordance with Amer-- icanPetroleum Institute specifications.

Both the girts and the diagonal braces are formed of angle-ironfabricated steel and placed in position with their flanges laterallyoutwardly directed, thereby facilitating assembly and providingadditional clearance in the interior of the derricks.

The legs 5, to which the girts and diagonal braces are attached, aremade up of staggered sections. The starting or bottom'leg sections areall of the same length and extend to the second girt l, but the next legsections consist of two full length sections and two half-lengthsections placed in diagonally opposite positions. Thereabove all the legsections are of full length until the top section which has twohalf-length leg sections and two full length leg sections are disposedin diagonal opposition. In a typical intermediate section of the derricksuch as shown in Figure 4 of the drawings the full length leg sectionscomprise a diagonally opposed pair ll which extend below the lower girtwith accompanying braces and a diagonally opposite pair of leg sectionsI8 which extend above the upper girt with accompanying braces. Thestaggering of the leg joints accomplished in this way interrupts anddisrupts the vibration frequency throughout the height of the derrickset up by the operation of the drilling equipment thereby substantiallyeliminating loosening of joints and shearing of bolts and liability tostructural failure at moments of overload. This, by construction-inconjunction with described arrangement of bracing, provides the greaterresistance of the derrick to twisting which is characteristic of thepresent invention.

In the top sections the braces I I, l2, l3 and I4 corresponding to thebraces of the intermediate sections are necessarily foreshortened andarranged at a more acute angle as is evident from Figure 6 of thedrawings.

The bolted leg joint construction employed in the present arrangementexhibits very exceptional superiority over present bolted joints inpoint of strength and in point of simplicity and ease of assembly. Asshown in Figure '7 of the drawings, the joint consists of two angle ironplates l9 and 20, respectively, fitted on the inside of and the outsideof the leg section 5, with bolts 2| and 22, respectively, being boltedthrough the respective flanges after the next leg member is placedbetween them. In this way a rigid joint is provided having a greaterload capacity than the calculated capacity of the leg section itself. Asindicated in the drawings the vertical flanges of the girts are boltedto the joints and bear directly against the outer angle-iron plates 20,thereby further adding strength and rigidity to the derrick as a whole.

On the rotary side the elements 23 and 24 which with the girt 9 definethe rotary opening, extend from the lower ends of the legs past the girt9 to the connection plate I6 at the girt Hi. In the panel bounded by thegirts 9 and In there is, besides the diagonal braces II, l2, I3, and M,a perpendicular brace 25 connected at its upper end to the plate l6 andat its lower end to a. junction 26 with the inner ends of the braces l3and I4. Proportioned diagonal braces 21 and 28 have their outer endsconnected together to the legs 5 in the panels below the girt 9 at therotary front of the derrick and have their inner ends connected atspaced points to the elements 23 and 24. Odd diagonal braces 23 in thelowermost panel connect with the elements 23 and 24 at the lower ends ofthe braces 28 and at their opposite ends with the legs 5, all as shownin Figure 2 of the drawings.

0n the ladder or forge sides of the derrick such as shown in Figure 3 ofthe drawings, the panel bounded by the girts 6 and I is different fromthe other panels by reason of the diagonal braces 30, 3| and 32, 33,respectively, which have their inner and upper ends connected to theplate H5. The outer and lower ends of the braces 30 and 32 are connectedto the legs 5 while the outer and lower ends of the braces 3| and 33 areconnected to the girt 6 at points spaced inwardly from the outer endsthereof, at plates 34 and 35, to which the upper ends of elements 36 and31 are also connected. The lower ends of the elements 36 and 31 areconnected to the lower ends of the legs 5. A perpendicular brace 38 isconnected between the middle of the girt 6 and the plate l6. Abbreviateddiagonal braces extend between the elements 36 and 3! and the adjacentlegs 5.

The construction described provides full conformity to AmericanPetroleum Institute specifications for the height, base, water tableopening, gin pole capacity and height, window openings for rotaries,clear opening for drawworks, bull wheel girt clearance.

Although I have shown and described herein structural details andarrangements of the preferred embodiment of my invention, it is to beunderstood that I do not wish to limit the application of my inventionthereto, except as may be required by the scope of the subjoined claims.

The words midway point and points midway as used herein are intended togenerally allocate the points involved, except in these instanceswherein exact location thereof is implicit, as slight variation awayfrom the center or middle of the parts involved is embraced within thescope of the invention.

Having described the invention, what is claimed as new is:

1. An oil well derrick or the like comprising stages each comprisingfour leg sections, vertically spaced girts secured to and betweenadjacent leg sections, diagonal braces extending between and connectedto points on the girts intermediate the ends of the girts and to pointson the leg sections intermediate the adjacent girts, two of thediagonally opposed leg sections extending above the upper girt and twoof the diagonally, opposed leg sections extending below the lower girt.

2. An oil well derrick or the like comprising four sectional cornerless, said legs comprising bottom sections of substantially the samelength, intermediate sections consisting of a first section havingdiagonally opposed full lengths and diagonally opposed half-lengths,with the full lengths projecting upwardly above the half lengths, andthe intermediate sections above said first section having diagonallyopposed full lengths forming pairs with the legs of one pair instaggered relation vertically to the legs of the other pair to connectwith the corresponding lengths of the first section and of upwardlysucceeding sections, and a top section having diagonally opposed halflengths and diagonally opposed full lengths to cooperate with thelengths on the uppermost intermediate section, and joint meansconnecting the related terminals of th lengths in end to end relation.

3. An oil derrick or the like in accordance with claim 2 wherein saidlengths comprise angleiron forms and said joint means comprises innerand outer angle-iron plates fitting the inner and outer sides of theterminals of the lengths, with bolts traversing the flanges of the formsand plates above and below the meeting point of the terminals.

4. An oil derrick or the like in accordance with claim 2 wherein saidlengths comprise angleiron forms and said joint means comprises innerand outer angle-iron plates fitting the inner and outer sides of theterminals of the lengths, with bolts traversing the flanges of the formsand plates above and below the meeting point of the terminals, saidderrick or the like further comprising angle iron girts having theirvertical flange engaged with the outer side of the outer angle ironplate with at least one bolt traversing said vertical flange, a relatedflange of each of the angle iron plates and the related flange of theleg length positioned therebetween.

5. An oil well derrick or the like comprising four sectional cornerlegs, said legs comprising bottom sections of substantially the samelength,

- intermediate sections consisting of a first section having diagonallyopposed full lengths and diagonally opposed half-lengths, with the fulllengths projecting upwardly above the half lengths, and the intermediatesections above said section having diagonally opposed full lengthsforming pairs with the legs of one pair in staggered relation verticallyto the legs of the other pair to connect with the corresponding lengthsof the first section and of upwardly succeeding sections, and a topsection having diagonally opposed half lengths and diagonally opposedfull lengths to cooperate with the lengths on the uppermost intermediatesection, and joint means connecting the related terminals of the lengthsrelation vertically to the legs of the other pair to connect with thecorresponding lengths of the first section and of upwardly succeedingsections, and a top section having diagonally opposed half lengths anddiagonally opposed full lengths to cooperate with the lengths on theuppermost intermediate section, and joint means connecting the relatedterminals of the lengths in end to end relation, and girts securedbetween the legs and to said joint means with diagonal braces extendingbetween and secured at one end to adjacent girts at a point adjacent tothe middle thereof and at their outer ends to the legs at a pointsubstantially midway between the adjacent irts.

CHARLES L. FOX.

